The Phoenix product catalog entitled “Leiterplattenanschluss COMBICON 2002” [COMBICON 2002 printed circuit board connection] discloses, for example on pages 3 and 318, a modular installation device which is provided with a housing and a top-hat rail holder and has removable screw terminal blocks which are provided with block-standardized coding for the purpose of supplying the blocks in the correct position, claw-like projections for the purpose of fixing them to the housing and contact needles with which contact is to be made axially. Such an installation device is used, for example, as a rail-mounted device in a switchgear cabinet and acts as a switching and/or protective switching device, signal converter or the like for the purpose of converting switching and/or control concepts.